[rescue] Spaceballs.

[Scott Newell]

Joshua D Boyd wrote:

>I think it works, but I'd have to double check.  Matrices are only for linear
>transformations, so the word Hexcone worries me, but I know I've seen
matrices
>given for HSV operations...

Then I probably don't know what I'm talking about... ;-)  My library isn't
very deep in color theory, although I was recently fascinated by the
Walter/Wendy Carlos page on retinex :


http://www.wendycarlos.com/colorvis/retinex.html


>BTW, a rotation in RGB color space is the same as a hue rotation in HSV 
>apparently.

That's wild!


> Apparently FFTs can be applied to any number of dimensions.  However, I also
> understood an FFT as something that required 2 inputs, a time and a
value, and
> returned to inputs, a frequency for that value.  In fact, most descriptions 
> I've read about FFTs state that it is a transformation from the time domain
> to the frequency domain.  Well, fine.  But, what is the time domain for a 
> single image?  Which is to day that I'm far from understanding the forces at
> work here.

Josh, go grab a EE signals and systems book, or a basic image processing
book.  They should cover both the 1d and 2d Fourier continuous and discrete
transforms.  It's a lot of fun to look at the mag and phase of 2d
transforms and compare to the original image.  

Here's something goggle turned up:
http://astronomy.swin.edu.au/pbourke/analysis/fft2d/


newell